The Enduring Arab Byzantine Conflict

Secretly the Arab Byzantine wars were the largest conflict in human history, lasting over 400 years of non-stop fighting. The Romans built massive walls across their entire empire just to keep the Arabs out. They even created Greek fire - liquid flames shot from boats that could burn on water. When the Arabs finally broke through, they found 100,000 Roman soldiers waiting. The battle lasted 5 months straight. By the end both empires were so exhausted they couldn't fight anymore. The conflict changed warfare forever - introducing siege weapons, naval tactics and defensive fortifications we still use today.